1. Field of the Invention
The present invention relates to an electromagnetic relay.
2. Description of the Related Art
As a device which is arranged in an electrical circuit to electrically connect and disconnect it, an electromagnetic relay is known. An electromagnetic relay is provided with an electromagnet which includes a coil, an armature which faces the electromagnet, and electrodes which are connected to the armature and include contacts. In the electromagnetic relay, when the coil is energized, the armature is pulled by the electromagnet causing the armature to move. Due to movement of the armature, a plurality of contacts are electrically contacted or separated.
Japanese Patent Publication No. 7-312161 discloses an electromagnet which is provided with a coil block, a plate shaped yoke which is fastened by being inserted between magnetic poles of the coil block and which forms a magnetic circuit with the iron core, and a block shaped permanent magnet which is provided at the center part of the plate shaped yoke. It is disclosed that the armature of the electromagnet is formed with a hole part, cutaway part, and recess part as parts for adjusting the magnetic resistance.
Japanese Examined Utility Model Publication No. 63-47000B2 discloses an electromagnet relay which fastens a spring component which includes a fixed contact spring and a moving contact spring integrally to an electromagnet component. In this electromagnetic relay, it is disclosed that a hole which is provided at a free end of the moving spring and a hole which is provided at a front end of the armature are connected by a drive card.
Japanese Patent Publication No. 9-245599A discloses an electromagnetic relay in which a coil block and contact operating mechanism are arranged separated on a base member and in which a moving piece which is attached to the coil block and the contact operating mechanism which includes electrodes having contacts are connected by a card. It is disclosed that the card of this electromagnetic relay has a bottom end which is locked with a lock hole of a moving contact piece and has a top end with a lock recess in which a lock projection which is formed on the moving iron piece is locked.
As disclosed in the above patent literature, it is known to arrange a card between an armature and electrodes to transmit the operation of the armature to the electrodes in the electromagnetic relay. The electromagnetic relay which is provided with the card is formed so that the card moves corresponding to the operation of the armature and the electrodes move corresponding to the operation of the card. The armature is formed by iron etc. since it is formed by for example a magnetic body. As opposed to this, the card is formed by an insulating material of resin etc.
In the production of an electromagnetic relay, the card has to be connected to the armature, but in the process of connecting the card to the armature, sometimes part of the card is scraped off. For example, sometimes the connecting part of a card is fit into a connecting part of an armature. The armature is formed by iron or another hard material, while the card is formed by resin or other soft material, so when fitting the card in the armature, sometimes the part of the card which slides against the armature is scraped off and scrapings are produced.
After assembling the electromagnet or the card or other inside parts, the inside parts are covered by a case. In this regard, the scrapings of the card sometimes remain in the case. If the scrapings of the card remain inside the case, for example, they sometimes stick to the contacts and cause poor connection between the contacts.
Further, an armature is sometimes formed with a narrow part for fitting the card. In this regard, sometimes the strength of the part for fitting the card is insufficient and the part for fitting the card deforms in the production of the armature. If the part for fitting the card was not formed to the desired shape, the armature is treated as defective.